Modern TVs are designed with advanced technology, but like any electronic device, they are prone to wear and tear over time. As a technician or professional repair specialist, identifying the root cause of a TV problems quickly and sourcing the right solution is essential. Below are five of the most common TV issues you’ll encounter and how to fix them professionally to ensure lasting results.

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1. No Picture or Black Screen

A TV that powers on but displays no image is one of the most frequent complaints from customers.

🔧 Possible Causes:

• Faulty TCON board failing to process image signals.
• Defective LED backlight strips causing the panel to stay dark.
• Damaged LVDS or ribbon cables connecting the main board to the panel.

✅ How to Fix:

• Test voltage output from the power supply and TCON board.
• Inspect the backlight using a tester or external light source to check for dim illumination.
• Replace the faulty TCON board or LED backlight strips with genuine, compatible parts.

👉 Parts Available: TCON Boards | LED Backlights

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2. Horizontal or Vertical Lines on the Screen

Lines appearing across the screen often point to panel communication issues or partial component failure.

🔧 Possible Causes:

• Failing TCON board affecting pixel control.
• Faulty panel or damaged COF (Chip-on-Flex) connections.
• Loose or oxidized ribbon cable contacts.

✅ How to Fix:

• Clean and reseat ribbon connectors.
• Swap in a tested TCON board to verify functionality.
• For panel-level faults, use bonding machines for COF repairs or consider panel replacement.

📌 Tip for Technicians: Always use anti-static tools and clean connectors with appropriate electronic contact cleaners to avoid future failures.

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3. TV Powers On and Off Repeatedly

Also known as a “boot loop,” this problem frustrates many users and usually indicates a power regulation or firmware issue.

🔧 Possible Causes:

• Defective power supply board delivering unstable voltage.
• Corrupted firmware or main board malfunction.
• Short circuits in backlight or other connected components.

✅ How to Fix:

• Test voltage rails from the power supply board and check for fluctuations.
• Isolate the backlight circuit to rule out overloads.
• Update or reflash the firmware; if unresolved, replace the main or power board.

👉 Parts Available: Power Boards

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4. Dim or Uneven Brightness

A common issue in LED and LCD TVs, uneven brightness is often misdiagnosed by customers but is usually straightforward for professionals to fix.

🔧 Possible Causes:

• Worn-out LED backlight strips.
• Voltage drops from a failing LED driver circuit.
• Heat damage causing partial LED failure.

✅ How to Fix:

• Test individual LED strips with a backlight tester.
• Replace all backlight strips together to maintain uniform brightness.
• Use thermal paste or cooling pads to improve heat dissipation and prevent future issues.

📌 Technician’s Note: At WeFix.lk, we also recommend using an LED dimmer to prolong backlight life and reduce overheating issues, especially in large TVs.

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5. No Sound or Distorted Audio

When the display works but audio fails, it’s often linked to main board or speaker issues.

🔧 Possible Causes:

• Defective audio IC on the main board.
• Damaged internal speakers or loose wiring.
• Firmware-related audio driver failure.

✅ How to Fix:

• Test the audio output using headphones or external speakers.
• Replace the audio IC or the entire main board if IC-level repair isn’t viable.
• Reflash firmware to rule out software-related issues.

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Why Professional Diagnosis Matters

While some issues appear similar, the underlying cause can vary between models and brands. As a technician, using proper diagnostic tools ensures accurate fault detection and avoids unnecessary part replacements.

At WeFix.lk, we support professionals by supplying genuine TV parts for all major brands, including TCON boards, main boards, power supply units, and backlight sets. Our parts are tested and warranty-backed, helping you deliver reliable repairs every time.

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Where to Source the Best TV Parts in Sri Lanka

Finding high-quality, compatible TV parts is crucial for professional repair success.

✅ Why choose WeFix.lk?

• Large inventory of genuine and tested TV components
• Competitive pricing for technicians and service centers
• Professional guidance to match exact part numbers
• Warranty on every product for peace of mind

📌 Explore our categories:

• TCON Boards
• LED Backlights
• TV Parts & Boards

📞 Contact us: 0757000028
📍 Visit us: No 12, Keyzer Street, Colombo 11, Pettah, Sri Lanka
🌐 Website: www.wefix.lk

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Conclusion

From black screens to no sound, most TV problems can be solved with accurate diagnosis and the right replacement parts. As a technician, ensuring you source high-quality components is the key to professional-grade repairs.

At WeFix.lk, we are dedicated to supporting Sri Lanka’s TV repair professionals with low price, best quality parts and expert support. Whether you need a TCON board, power supply, or backlight set, we’ve got you covered for every repair challenge.

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